drm/amdgpu: remove redundant outer loop and remove commented out code

The outer loop is redundant and can be removed as it is doing nothing
useful. Also remove some commented out code that is not being used.

Detected by CoverityScan, CID#1402073

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>